The development of triggerable systems that allow precise control of the timing, duration and magnitude of drug release is important for therapeutic medicine. Micellar aggregates (core-shell micelles, vesicles, etc.) formed by amphiphilic block copolymers or small molecule surfactants have been reported as possible light-activatable drug delivery systems (Jiang, J., Tong, X., Morris, D. & Zhao, Y. Toward photocontrolled release using light-dissociable block copolymer micelles. Macromolecules 39 (2006); Jiang, J., Tong, X. & Zhao, Y. A new design for light-breakable polymer micelles. Journal of the American Chemical Society 127 (2005)). In this sense, polymer micelles could release the drugs at a required time and tumor location. In some cases the dissociation of the micelles occurs due to structural arrangements of the photo-sensitive molecule attached to the block copolymer or surfactant. In other cases, the interaction of the photo-sensitive molecule with light results in a structural change that alters the hydrophilic/hydrophobic balance toward the disassembly of the micelle (Babin, J. et al. A new two-photon-sensitive block copolymer nanocarrier. Angew Chem Int Ed Engl 48, 3329-3332 (2009)). Recently, these studies have been extended to NPs that disassemble in reaction to light (Fomina, N., McFearin, C., Sermsakdi, M., Edigin, O. & Almutairi, A. UV and near-IR triggered release from polymeric nanoparticles. J Am Chem Soc 132, 9540-9542 (2010); Timko, B. P., Dvir, T. & Kohane, D. S. Remotely triggerable drug delivery systems. Adv Mater 22, 4925-4943 (2010)). However, the demonstration that these systems can be used to release efficiently biomolecules within cells either in vitro or in vivo with precise temporal and dosage control remains elusive. These systems should be formed by (i) components that can be eliminated by the human body while being able to (ii) efficiently cross the cell membrane and (iii) disassemble by light releasing consequently the cargo.
Additionally, retinoic acid (RA) as a differentiation agent is used in the clinic for the treatment of human chronic myelogenous leukemia (CML), human acute promyelocytic leukemia (APL) and acute myeloid leukemia (AML) (Warrell, R. P., Jr. et al. Differentiation therapy of acute promyelocytic leukemia with tretinoin (all-trans-retinoic acid). N Engl J Med 324, 1385-1393 (1991); Russo, D. et al. All-trans retinoic acid (ATRA) in patients with chronic myeloid leukemia in the chronic phase. Leukemia 12, 449-454 (1998)). RA activates nuclear RA receptors (RARs) that forms heterodimers with retinoid X receptors (RXRs) which in turn binds to the RA response element (RARE) resulting in the activation of target genes causing cell growth arrest, apoptosis and differentiation (Si, J., Mueller, L. & Collins, S. J. CaMKII regulates retinoic acid receptor transcriptional activity and the differentiation of myeloid leukemia cells. J Clin Invest 117, 1412-1421 (2007). However, in some cases, the intracellular concentration of RA available is relatively low to induce significantly the differentiation of leukemia cells, due to the low solubility of RA in physiologic milieu and low capacity to accumulate in cell cytoplasm.
So, in order to overcome the problems of the state of the art, the present invention and different embodiments established an opto-nanomedicine approach for the treatment and study of leukemic (stem) cells either in vitro or in vivo. This new technology allows remote control in the release of biomolecules with spatio-temporal resolution. The light-activatable NPs disclosed are suitable for general therapeutic and regenerative medicine applications.
The NP formulation described here is irreversible disassembled by a photochemical process (UV or blue laser). Several light-activatable polymeric NPs have been reported12, however the internalization and intracellular trafficking of these NPs containing bioactive agents and their effect in the modulation/differentiation of cells both in vitro and in vivo has not been studied. Here, we demonstrate the precise spatial and temporal control in the release of RA. We show for the first time that cells transfected with light-activatable NPs can be activated after 2 days while maintaining the same inductive properties. This gives an opportunity to use cells as “Trojan horses” for activation at specific sites of human body.
Although several NP formulations have been reported for the release of RA, including from our group, no formulation can release high doses of RA (120 μg of RA per mg of NP) in minutes-range. This is very important to enhance the differentiation of leukemic cells, in particular in APL caused by PLZF/RARα, which exhibits impaired sensitivity to RA. In this case, the light-activated RA+NPs enhanced 2-4 fold the differentiation of the leukemic cells as compared to cells treated with non-activated RA+NPs.
These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.